1. Technical Field
The present invention relates to a technique to measure a magnetic field generated from a living body.
2. Related Art
As a sensor to measure a very weak magnetic field generated from a heart or a brain, a SQUID (Superconducting Quantum Interference Device) sensor is known (see JP-A-11-253412, JP-A-2000-41965, JP-A-2008-86675, JP-A-7-77564, JP-A-2006-754403, JP-A-2006-94984 and JP-A-2005-80951).
In general, when a magnetic field is measured by using a magnetic sensor, in order to raise spatial resolution, it is necessary to miniaturize the magnetic sensor and to increase the number of magnetic sensors per unit area. However, if the magnetic sensor is miniaturized, the sensitivity becomes low, and accordingly, a very weak magnetic field can not be measured.